In this lesson, students practice using and creating functions with parameters. Students learn that writing functions with parameters can generalize solutions to problems even further. Especially in situations where feel like you are about to duplicate some code with only a few changes to some numbers, that is a good time to write a function that accepts parameters. In the second half of the lesson, students make a series of modifications to a program that creates an “Under the Sea” scene by adding parameters to functions to more easily add variation to the scene. Lastly, students are introduced to App Lab’s random number functions to supply random values to function calls so the scene looks a little different every time the program runs.

Students learn to use random values and looping to create variation in their drawings and quickly duplicate objects they wish to appear in their digital scenes many times. Students will be presented with a version of the for loop which only enables them to change the number of times the loop runs. This block is essentially a "repeat" block and will be presented that way. Students will also be presented with blocks which enable them to choose a random number within a given range. Together these blocks enable students to create more complex backgrounds for digital scenes by randomly placing simple objects within the background of their scene. Students use these tools to step through the Under the Sea exemplar digital scene.

To conclude their study of big data and cryptography, students will complete a small research project related to a dilemma presented by Big Data or Cybersecurity, in the form of a Practice Performance Task. Students will pick one of two issues to research more deeply - either an issue related to big data, or one related to cybersecurity. Students will need to identify appropriate online resources to learn about the functionality, context, and impact of the technological innovation that gave rise to the dilemma they are investigating. After completing their research, students will present their findings both in a written summary and with an audio / visual artifact they found online. The written components students must complete are similar to those students will see in the AP Performance Tasks.

This project is an opportunity to practice many of the skills students will use when completing the Explore Performance Task on the AP® Exam at the end of the year. While an open-ended research project might be intimidating, students have built all the skills they need to complete this task.

**Note:** This is NOT the official AP® Performance Task that will be submitted as part of the Advanced Placement exam; it is a practice activity intended to prepare students for some portions of their individual performance at a later time.

**Note for 2017-18 School Year:** This Practice PT has NOT been updated to reflect changes to the [Explore PT Scoring Guidelines](https://apcentral.collegeboard.org/pdf/2018-explore-performance-tasks-sg.pdf) released in Fall 2017. We recommend you review those guidelines to understand the similarities between this project and the actual Explore PT.

Students learn about various types of cybercrimes and the cybersecurity measures that can help prevent them. Then students perform a Rapid Research project investigating a particular cybercrime event with a particular focus on the data that was lost or stolen and the concerns that arise as a result. The Rapid Research activity features vocabulary, concepts, and skills that should help prepare them for the AP Explore PT, and also serves as a capstone for the sequence of lessons on encryption and security.

In this lesson, students are introduced to the concept of “[v big data],” where it comes from, what makes it “big,” and how people use big data to solve problems. Students are asked to consider how much of their lives are “datafied” or could be, and the teacher will show the projected growth of data in the world. Students will then investigate a big data tool in pairs to evaluate the tool for its usefulness and investigate the source of the data used to make the tool. A key take-away from the lesson is that different considerations need to be made when trying to look at, use, or analyze tools that use big data. The world of big data is big, and we’ve only begun to figure out how to solve problems with it.

The lesson concludes with a brief introduction to the AP Explore Performance Task which students are recommended to complete at the end of the unit.

Students use the Google Trends tool in order to visualize historical search data. They will need to identify interesting trends or patterns in their findings and will attempt to explain those trends, based on their own experience or through further research online. Afterwards, students will present their findings to ensure they are correctly identifying patterns in a visualization and are providing plausible explanations of those patterns.

This lesson asks students to consider carefully the assumptions they make when interpreting data and data visualizations. The class begins by examining how the Google Flu Trends project tried and failed to use search trends to predict flu outbreaks. They will then read a report on the Digital Divide which highlights how access to technology differs widely by personal characteristics like race and income. This report challenges a widespread assumption that data collected online is representative of the population at large. To practice identifying assumptions in data analysis, students are provided a series of scenarios in which data-driven decisions are made based on flawed assumptions. They will need to identify the assumptions being made (most notably those related to the digital divide) and explain why these assumptions lead to incorrect conclusions.

In this lesson students will conduct a small amount of research to explore a computing innovation that leverages the use of data. Students will research a topic of personal interest and respond to questions about about how that innovation produces, uses, or consumes data. The lesson is intended to give students practice with doing research of this nature and provides a small amount of scaffolding to help students figure out what to look for.

This lesson is intended to be a quick, short version of a performance task in which students rapidly do some research and respond in writing. It might take 2 class days but should not take more. The goal is to generate ideas for exploration later when students complete the actual Explore PT later in the year.

Students begin this lesson by investigating some of the world’s biggest data breaches to get a sense for how frequently data breaches happen within companies and organizations, and what kinds of data and information is lost or given up. Afterwards, students will use the Data Privacy Lab tool to investigate just how easily they could be uniquely identified with a few seemingly innocuous pieces of information. At the conclusion of the lesson, students will research themselves online to determine just how much someone could learn about them by conducting the same searches and “connecting the dots.”

This lesson focuses on the economic and consumer concerns around apps and websites that collect and track data about you in exchange for providing you a service free of cost. Often the quality of the service itself is dependent on having access to data about many people and their behavior. The main take-away of the lesson is that students should be more informed consumers of the technology around them. They should be able to explain some of the tradeoffs between maintaining personal privacy and using innovative software free of cost.

In this lesson, students are introduced to the need for encryption and simple techniques for breaking (or cracking) secret messages. Students try their own hand at cracking a message encoded with the classic Caesar cipher and also a Random Substitution Cipher. Students should become well-acquainted with idea that in an age of powerful computational tools, techniques of encryption will need to be more sophisticated. The most important aspect of this lesson is to understand how and why encryption plays a role in all of our lives every day on the Internet, and that making good encryption is not trivial. Students will get their feet wet with understanding the considerations that must go into making strong encryption in the face of powerful computational tools that can be used to crack it. The need for secrecy when sending bits over the Internet is important for anyone using the Internet.

In this lesson, students examine a classic problem in computer science, the Traveling Salesperson Problem (TSP). Students solve small instances of the problem, try to formulate algorithms to solve it, and discuss why these algorithms take a long time for computers (and humans) to compute. Students see how the TSP grows in size much faster than the problem of adding characters to a password. Even though we use encryption to motivate a desire to learn about computationally hard problems, they are valuable to know about, in and of themselves. This lesson covers some territory about how we reason formally and mathematically about algorithms and figuring out how “hard” something is for a computer to do.

In this lesson, students continue their exploration of computationally hard problems as they investigate a one-way function, a problem which is easy to construct in such a way that you know the solution, but it is computationally hard to solve. Students will begin the lesson by trying to solve the “Wireless Hotspot Problem” (also know as the vertex cover or dominating sets problem) to experience first-hand the challenge of solving it. They will then be instructed on how easy it is to create such a problem and will practice doing so themselves. In the Wrap-up, students are introduced to the concept of a one-way function and consider why such problems might be useful tools when constructing methods of encryption. If it’s easy to create a problem that is hard for a computer (or human!) to solve, then perhaps it is possible to make truly secure encryptions.

In this lesson, students learn about the relationship between cryptographic keys and passwords. Students explore the Vigenère cipher with a widget to examine how a cryptographic "key" can be used to encrypt and decrypt a message. Then, students use a tool that shows them about how long it would take to crack a given password using a standard desktop computer. Students experiment with what makes a good password and answer questions about the “human components” of cybersecurity.

This is a big multi-part lesson that introduces the concept of public key cryptography which is an answer to the crucial question: *How can two people send encrypted messages back and forth over insecure channels (the Internet) without meeting ahead of time to agree on a secret key?* In a nutshell, there are two main principles we want students to understand:

1. The mechanics of communication with public key cryptography
2. The basic mathematical principles that make it possible

The lesson gets at these two core ideas through a deliberate chain of thought experiments, demonstrations, activities and widgets. All parts are building blocks that lead to deeper understanding of how it works.

This lesson attempts to walk students through the iterative development process of building an app (basically) from scratch that involves the use of `if` statements. Following an imaginary conversation between two characters - Alexis and Michael - students follow the problem solving and program design decisions they make for each step of constructing the app. Along the way they decide when and how to break things down into functions, and of course discuss the logic necessary to make a simple game.

The last step - writing code that executes an end-of-game condition - students must do on their own. How they decide to use `if` statements to end the game will require some creativity. The suggested condition - first to score 10 points - is subtly tricky and can be written many different ways.

At the conclusion of the lesson there are three practice Create PT-style questions as well as resources explaining the connection between this lesson and the actual Create PT. Depending on how you use these materials they can easily add an additional day to this lesson.

This lesson demonstrates how a slight manipulation of a conditional statement can allow for the creation of a new and powerful tool in constructing programs, a **while** loop. Students are introduced to a **while** loop by analyzing the flow chart of a conditional statement in which the "true" branch leads back to the original condition. Students design their own flowcharts to represent a real-world situation that could be represented as a **while** loop, and they learn how to recognize common looping structures, most notably infinite loops. Students then move to App Lab, creating a **while** loop that runs exactly some predetermined number of times. While learning about creating **while** loops, students will be introduced to many of the common mistakes early programmers make with **while** loops and will be asked to debug small programs. They finally progress to putting if statements inside a while loop to count the number of times an event occurs **while** repeating the same action. This activity will recall the need for counter variables and foreshadows their further use in the following lesson.

In this lesson, students gain more practice using **while** loops as they develop a simulation that repeatedly flips coins until certain conditions are met. The lesson begins with an unplugged activity in which students flip a coin until they get 5 heads in total, and then again until they get 3 heads in a row. They will then compete to predict the highest outcome in the class for each statistic. This activity motivates the programming component of the lesson in which students develop a program that allows them to simulate this experiment for higher numbers of heads and longer streaks.

This lesson introduces arrays as a means of storing lists of information within a program. The class begins by highlighting the difficulties that arise when trying to store lists of information in a variable. Students then watch a short video introducing arrays and a subset of the operations that can be performed with them. Students will work in Code Studio for the remainder of the class as they practice using arrays in their programs. At the conclusion of the sequence, students build a simple app which can be used to store and cycle through a list of their favorite things. In the next lesson, students will continue working with a version of this app that can display images and not just text strings.

Students will extend the **My Favorite Things** app they built in the previous lesson so that it now manages and displays a collection of images and responds to key events. Students are introduced to the practice of refactoring code in order to keep programs consistent and remove redundancies when adding new functionality. As part of learning to use key events, students are shown that event handlers pass a parameter which contains additional information about the event. This lesson also serves as further practice at using arrays in programs.